Automatic fabric feeder device for sewing machines



Nov. 14, 1967 BONO 3,352,262

AUTOMATIC FABRIC FEEDER DEVICE FOR SEWING MACHINES Filed April 8, 1965 4 Sheets-Sheet 1 J FIG] I Nov. 14, 1967 BONC) 3,352,262

AUTOMATIC FABRIC FEEDER DEVICE FOR SEWING MACHINES Filed April 8, 1965 4 Sheets-Sheet 2 AUTOMATIC FABRIC FEEDER DEVICE FOR SEWING MACHINES Filed April 8} 1965 4 Sheets-Sheet 5 L. BONO Nov. 14', 1967 AUTOMATIC FABRIC FEEDER DEVICE FOR SEWING MACHINES 4 Sheets-Sheet 4 Filed April 8, 1965 mdI m m a mm mm mm om 0 0 mo mm m: om

United States Patent Office 3,352,262 Patented Nov. 14, 1967 17 Ciairris. or. 112-2 ABSTRACT 6F THE DESCLGSURE A sewing machine having a fabric feeder device for maintaining a fabric in a taut condition while advancing same past the sewing needle, said feeder device being adjustable to successively accommodate various lengths of fabric in said taut condition but being adapted to automatically maintain any particular adjustment in order to repetitively accommodate fabric pieces of the same length, said feeder device comprising two independently reciprocable fabric clamping means interconnected to each other by a connection means which is adjustable to maintain said clamping means spaced apart from each other for either of various fixed distances, said connection means also being adapted to permit independent movement of said clamping means relative to each other and then to automatically re-establish the pre-adjusted fixed distance therebetween.

The present invention is directed to an improved device for automatically feeding fabric to the sewing station on a sewing machine. Such device has particular applicability in the case of sewing machines which are adapted to sew stitches in separate groups, as for example, in the sewing of buttons, the sewing of buttonholes, or the sewing of stitches in accordance with a pattern comprising spaced groups of stitches.

Various types of such automatic devices are already known, in which are usually provided two pincers or fabric clamps which hold the fabric edges. These clamps are usually mounted on a corresponding number of sliding carriages, one of which performs the function of pulling and positioning the work fabric relative to the sewing needle, while the second performs the function of holding said fabric fixed in place during the actual sewing steps. In such known devices there is no connection between the two carriages other than the work fabric itself which serves to drag the second carriage along in response to a movement of the first carriage. This results in a stretching and lengthwise deformation of the fabric since it alone bears the pulling force transmitted from the first to the second carriage. This drawback is especially serious when the fabric is an elastic or stretch fabric since, as is obvious, the fabric will be sewn while in stretched condition resulting in an incorrect positioning and spacing of the groups of stitches.

It is therefore an object of this invention to provide an automatic fabric feeding device wherein the fabric itself is not subjected to any undesired tension or stretching forces.

It is a further object to provide such a device wherein a suitable mechanical connection is provided between the two fabric carriages, this connection serving to transmit pulling forces from one carriage to the other.

Another object of this invention is to provide such a device wherein the distance between the respective carriages is maintained constant durin the successive sewing cycles.

Another object of this invention is to provide such a device wherein the fabric may be shifted by the ma- 2 chine presser foot without the second carriage also being shifted thereby.

A further object of the present invention is to provide such a device wherein the mechanical connection between the two carriages is automatically interruptable at the termination of the sewing process, and wherein said connection is successively restorable to re-establish the starting relationship to begin another sewing process.

These and other objects which will become apparent from the following detailed description which is referred to the accompanying drawings, in which:

FIGURE 1 is a vertical side view of a sewing machine according to this invention, mounted on a work table;

IGURE 2 is a vertical sectional front view of the machine of FIGURE 1;

FIGURE 3 is a perspective view showing in detail the second carriage of the automatic fabric feeding device;

FIGURES 4 and 5 are sectional views of the carriage of FIGURE 3 with FIGURE 4 being taken along line IV-IV of FIGURE 5.

With reference to FIGURES 1 and 2, the sewing machine 2 is mounted on top of a work table 1. The work fabric is intended to be moved from right to left (FIG- URE 2) under the needle bar 3 and needle 4. The machine 2 may be either a type for sewing buttonholes, buttons onto a fabric, or for sewing according to any cyclic or group arrangement of stitches. The machine also comprises a presser foot 5.

The automatic fabric feeding device includes two carriages, one of which, 13, is for gripping the leading edge of the fabric and the other of which, 14, is for gripping the trailing edge of the fabric. For this fabric .gripping purpose, carriage 13 is provided with clamp or pincer 11 and carriage 14 is provided with clamp or pincer 12.

Generally, the leading and trailing ends of the fabric are respectively gripped by clamps 11 and 12 and the fabric is advanced from right to left (FIGURE 2) under needle 4 by carriage 13 sliding vertically downward along the left side of the table 1 and carriage 14- sliding from right to left along the upper portion of the table. The carriages intermittentiy stop in order to permit the needle to effect a cycle or group of stitches. While the carriages are stopped, the presser foot 5 advances the fabric the required amount in order to effect a particular group of stitches, without, however, moving the trailing end carriage 1 5 and without releasing the trailing end clamp 12. When that particular group of stitches is completed, the presser foot rises, thereby releasing the fabric and the two carriages advance to the next sewing position at which a successive group of stitches is effected at a particular spacin from the preceding group.

After completing all the groups of stitches, the sewing machine 2 stops automatically, clamps 11 and 12 automatically open to release the fabric, and carriages 13 and 14 return to their starting positions.

The leading end carriage 13 is slidably mounted on two vertical guide rods 15 and 21 which are rigidly fixed to table 1. Clamp 11 includes a jaw 22 fixed on the structure of carriage 13 and a movable jaw 23 which is actuated by pivoted lever 24 for opening and closing the two jaws relative to each other.

In order to vertically slide carriage 13 in either direction along guide rods 15 and 21, a drive mechanism is provided, and this includes a motor 45 which is drivingly connected through an electromagnetic clutch and reducer (not shown) to a pair of parallel spaced sprocket chains 31, 31. The sprocket chains are each mounted on respective pairs of identical sprocket wheels 41-43. The wheels at each end of the chains are axially aligned with each other so that the chains are superimposed as seen in FIGURE 2. The upper wheels 43, 43 are the drive 3 wheels, these being coupled to the motor 45 through the aforementioned electromagnetic coupling and reducer. Said coupling is mounted 'within housing 44 which also rotatably supports the upper sprocket wheels 43, 43, the lower wheels 41, 41 being respectively journalled on pivot means 42, 42. The housing 44, motor 45, and pivot means 42, 42 are all supported by the work table 1, and the chains are also parallel to the guide rods 15, 21.

A pin 33 is secured between the parallel chains 31, 31, and a connecting rod is secured at its opposite ends to the pin 33 and to the carriage 13, so that vertical movement of the chains acts through rod 25 to vertically move the carriage 13.

The carriage 13 is automatically brought to a stop at various successive vertical positions by means of a position control rod 46 which extends parallel to and in close proximity to the guide rods. A number of positioning blocks 47 to 52 are axially adjustably mounted at spaced intervals along the rod 46.

Carriage 13 includes a pivoted lever at one free end of which is mounted a grooved member 53. The groove in member 53 is wide enough to embrace each positioning block and when engagement occurs, the carriage 13 presses downwardly upon the rod 46 which is axially displaceable to a certain extent. The downward axial displacement of rod 46 actuates suitable electromechanical devices (not shown) which causes the machine 2 to run andto effect a sewing stage. When this stage is completed, an electromagnet 54 operates to pivot the lever upon which part 53 is mounted, in a direction whereby part 53 moves radially away from the particular positioning block. with which it was engaged. The rod 46 then rotates about its longitudinal axis, this rotation serving to actuate the aforementioned electromagnetic clutch which results in the chains 31, 31 being driven in direc tion X by motor and carriage 13 being driven by said chains. This process continues until a finger 55 carried by the carriage 13 comes into contact with cam 56 which is axially adjustable along rod 57 which in turn is rigidly mounted on table 1 in parallel relationship with rods 15, 21, and 46. Contact finger 55 thereupon acts to open clamp 11, to which it is suitably connected, to thereby release the leading end of the fabric.

This automatic opening of clamp 11 alsoacts through appropriate means to pivot part 53 out of the axial path of the blocks 47 to 52 so as to exclude any possibility of contact between part 53 and any of said blocks. The carriage 13 is, therefore, free to perform a downward delivery stroke and a subsequent upward return stroke, at the end of which. a trip member 58, mounted on table 1, trips part 53 so that it is free to engage the topmost block 47. Since block 47 is the topmost or first block in the series, the electrical circuitry of the machine is arranged so that the machine 2 does not start as soon as part 53 engages this first block 47. In order to start the.

machine for each first sewing stage, a start button on panel 59 must be actuated by the machine operator.

During the return (upward) stroke of carriage 13, carriage 14 remains locked inits last position in order to permit the operator to release the trailing end of the fabric from clamp 12 and to insert the trailing end of another piece of fabric in the clamp 12. After this is accomplished, carriage 14 is released and it automatically returns (to the right in FIGURE 2) to its starting position at the same pre-established distance from carriage 13 as existed during the sewing of the preceding piece of fabric.

Since, generally'in machines for sewing buttonholes or buttons with four holes, during each sewing stage the presser foot 5 moves. in a pre-determined direction dragging the fabric along with it, the carriages 13 and 14 must permit such shifting of the fabric. In the present device, this is permitted without moving either carriage itself.

The trailing carriage 14 (FIGURES 2 and 3) is slidably mounted on horizontal guide 60 which is rigidly mounted on table 1 beneath the working platform 61v of said table. Carriage 14 is biased towards the right (its starting position) by a weight 62wl1ich is vertically slidable along guide rod 63 which is fixed to table 1. Weight 62 is connected to a pin 40 carried by carriage 14 by means of a cable 64 which passes over grooved roller 65 carried by the top of rod 63. At the lower end of rod 63, a cylinder 66 acts as a dash pot to cushion the downward falling of weight 62. This cylinder has an upper open end and a lower closed end and the weight 62 slides into the open end thereby compressing the air trapped in the cylinder.

Carriage 14 comprises a pair of sliding brackets 67 and 63 which embrace the opposite edges of guide 60 to permit carriage 14 to slide therealong. An upwardly extending wall 70 on the carriage has a pivot pin 69 fixedly mounted thereon, and clamp 12 is pivotably mounted on this pin. A spring 71 is connected at one end to the clamp 12 and at its other end it is anchored to the carriage structure so that clamp 12 is normally biased in a direction away from that in which the presser foot 5 shifts the fabric. Therefore, the fabric may be moved relative to carriage 14 under urging of the presser foot 5 by virtue of clamp 12 being movable against the tension of spring 71, this spring returning the clamp and fabric to their original positions once the presser foot releases the fabric. It will be noted that the dragging force of the presser foot is sufiicient to stretch spring 71 but is insufficient to overcome the force of weight 62 so that clamp. 12 pivots without shifting the position of carriage 14.

Clamp 12 comprises (FIGURE 5) a lower fixed jaw 72 fixed on an arm 73, and an upper movable jaw 74 which is pivotably mounted on block 75 which in turn is pivoted to a portion of arm 73. A lever 76 is used to open and close these jaws and a spring 77 biases jaw 74 to a closed position.

Carriages 13 and 14 are connected together through a means which absorbs the force, of weight 62 so that the force of this weight is not transmitted through the fabric which is held between the two carriages. This means comprises a cable 7 8 extending between the two carriages and having one end 79 fixed to carriage 13 while its other end is fixed to drum 80 by means of plate 81. Drum 80 is rotatably mounted on carriage 14 in order to wind cable 78 thereon whenever the distance between the carriages becomes less than the pre-established distance. In order to avoid overlapping of cable 78 on drum 80, said drum comprises a threaded hub 82 which is threadedly pivoted on a stationary threaded pivot pin 83 so that as the drum 80 rotates it also moves axially along the pin 83 and thereby winds cable 78 in successive nonoverlapping loops. The opposite ends of pin 83 are supported, respectively, in seat 84 in side wall 70 and in slot 85 in side wall 86 of the carriage structure. -A nut 88 and washer 87 lock the pin 83 in place. A fixed plate 90 having a guide hole 89 serves to guide the cable 78 onto the drum.

Drum 80 is urged to rotate by a wound spiral spring 91 which is housed in barrel 92 and has one end 93 extending through notch 94 in one end 95 of pin 83 and its other end 96 fixed by a rivet 97 to the circumferential wall of barrel 92. Barrel 92 is freely rotatable about the smooth end portion 95 of pin 83 and includes a transverse pin 98 fixed to the radial face of the barrel and axially extended into a hole 99 in radial wall 100 of drum 80. It is seen, therefore, that although the drum and barrel are rotatably connected together by virtue of pin 98, the barrel 92 does not follow the transverse, axial shifting of said drum along the threaded pin 83.

A split locking ring 101, split at 102, is adjustably rigidly mounted on hub 82 of drum 80, by means of locking screw 103. A hole 104 extends radially into the surface of ring 101 and receives therein a detent or pin 105 provided at the end 106 of an arm 107 of an oscillating locking lever which is pivotably mounted on pin 108 which in turn is fixedly mounted on the rear part of the carriage structure (FIGURE 4). This lever comprises arm 109 extending oppositely from arm 107, relative to pivot pin 108, and arm 109 rigidly mounts a transverse abutment pin 110 which is parallel to pin 108. Pin 108 protrudes laterally through wall 86 and on the protruding portion is pivotably mounted a notched plate 111 which comprises a trip means and includes two pairs of peripheral notches or steps 112, 113 and 114, 115. The notches 114 and 115 are adapted to alternately engage pin 110.

Notched plate 111 also includes a rigid pin 116 (FIG- URE 3). A spring 117 has its opposite ends respectively anchored to pin 116 and to pin 118, this latter pin rigidly extending from side wall 86 and located oppositely to pin 116 with respect to the axis of pin 108. It will, therefore, be seen in FIGURE 3 that notched plate 111 will either be urged clockwise, that is, with notch 114 pressing downwardly on pin 110, or that it will be urged counterclockwise, that is, with notch 115 pressing upwardly on pin 110. This dual action of spring 117, whereby it alternately urges plate 111 in opposite pivotal directions, can be termed a tumbler action and it results from the fact that the straight line which joins the axis of pin 118 with the axis of pin 116 extends either below (as in FIGURE 3) or above the axis of pin 108, depending upon where pin 116 is located relative to pin 108. When pin 110 is pressed downwardly, pin 105 will be engaged in radial hole 104 in the drum hub 101, while when pin 110 is pressed upwardly, pin 105 will be pivoted out of said hole. In the first case, the drum 80 will be prevented from rotating while in the second it will be free to rotate.

This freedom to rotate is necessary when the leading carriage 13 disen-gages from the bottomrnost block 52 and begins its final descending movement before it reverses and rises to its topmost position. When carriage 13 is at its position where it engages block 52, the rear carriage 14 is at the end of its stroke; therefore, the final descending movement of carriage 13 when it leaves block 52, requires that the carriage 13 move further away from carriage 14 and this is provided for by the aforementioned release of drum 80 when pin 105 moves out of hole 104.

In order to bring about this movement of pin 105 out of hole 104 at the instant when carriage 13 has disengaged block 52, a limit stop 121 is provided on table 1 in the path of arm 113 on notched plate 111. Arm 113 abuts against stop 121, while carriage 14 is close to the end of its leftward travel, and pivots plate 111 counterclockwise against the tension of spring 117. When plate 111 has pivoted a certain extent, pin 116 will have shifted to a point above the axis of pin 108 whereby spring 117 will contract and snap plate 111 further counterclockwise until notch 115 presses against pin 110 and thereby causes lever 100407 to pivot and to withdraw pin 105 from hole 104. Upon this occurring, another arm 112 of plate 111 abuts another surface of stop 121 in a manner whereby carriage 14 is locked in position at the end of its stroke.

In the meantime, carriage 13 continues its downward movement and unwinds cable 78 from drum 80, which is now rotating against the urging of spring 91 to permit this unwinding to occur. When carriage 13 reaches its lowest position it reverses direction and travels upwardly and spring 91 now acts to reverse the rotation of drum 80 and to rewind cable 78 onto the drum 80. Therefore, cable 78 is never slack, but always taut between the carriages.

While carriage 14 is stopped at its leftmost position, the machine operator may release the trailing end of the fabric from clamp 12 while carriage 13 is performing its upward stroke to its starting position.

When a new piece of fabric has been inserted in clamp 12, the operator presses against portion 120 at the end of lifter lever 119 which is rigidly mounted on carriage 14. This causes block 121 to press against arm 112 of plate 111 and to pivot plate 111 clockwise to the position where notch 114 again engages pin 110. Pin 105 will not, however, be able to enter hole 104 because drum 80 has been axially displaced along threaded pin 83 during its winding up of the cable 78. This pivoting of plate 111 releases carriage 14 from stop 121, and weight 62 pulls carriage 14 to its starting position with drum 80 rotating to unwind cable 78 as the distance between the carriages increases. When carriage 14 has finally reached its starting position the hole 104 will be aligned with pin 105 so that said pin can again lock the drum 80.

The operator can nOW insert the new leading end of fabric into clamp 11 and suitably stretch the fabric between clamps 11 and 12.

When it is desired to change the fixed distance between the two carriages, it is necessary to loosen screw 103 thereby freeing ring 101 from hub 82, taking care to maintain the connection between pin 105 and hole 104. Carriage 14 is then shifted in either desired direction until the new desired distance between carriages is attained, and finally, the ring is again secured onto the hub 82.

It will be understood that many obvious modifications will be possible relative to the preferred embodiment herein disclosed but that all such modifications are intended to be within the scope of the following claims.

What is claimed is:

1. In a fabric sewing machine which includes a sewing needle, an automatic fabric feeder for advancing a fabric under said needle in a feed direction, said feeder comprising: first and second carriages, each comprising a fabric holding clamp and each being movable from 'a respective starting position to an end position relative to said needle, a drive mechanism drivingly connected to said first carriage for moving said first carriage from its starting to its end position, automatic control means for intermittently stopping said first carriage at various sewing positions between said starting and end positions, said carriages being independently movable relative to each other, connection means connecting said second carriage to said first carriage and maintaining a constant spacing therebetween during the travel of said carriages from said starting to said end positions thereof, said connection means being releasable to permit said carriages to move further apart or closer together, the fabric clamp on said second carriage being movable in a direction parallel to said feed direction, a resilient means biasing said second carriage clamp in a direction opposite to said feed direction, said machine also comprising a presser foot which is movable along said feed direction, the clamps on said carriages being adapted to hold a fabric in taut condition between said carriages, said presser foot being adapted to grip a portion of said fabric and to advance said portion under said needle while said first carriage is stopped at respective ones of said sewing positions, said second carriage clamp being movable against the bias of said resilient means to permit said portion of fabric to be advanced by said presser foot while said connection means maintains said constant spacing between said carriages.

2. The machine of claim 1, wherein said connection means comprises a rotatable drum on said second carriage and a flexible cable connected at one end thereof to said drum and at its other end to said first carriage, and a biasing means urging said second carriage to its starting position, releasable locking means to fix said drum in a rotative position or alternatively to free said drum for rotation in either direction.

3. The machine of claim 2, comprising a means for releasing said locking means when said second carriage is at its end position.

4. The machine of claim 2, including a resilient means urging said drum to rotate in a direction to wind said cable thereon, such rotation being prevented by the action comprises a locking ring coaxially mounted with said drum and releasably fixed thereto, said ring being rotatable together with said drum when fixed thereto and being rotatable relative to said drum when released therefrom, said second carriage comprising a pivoted locking lever, inter-engaging means on said ring and said lever, said inter-engaging means being engageable with each other and thereby preventing rotation of said drum in either direction.

8. The machine of claim 7, wherein said interengagin-g means comprises a hole in the circumferential periphery of said ring and a detent in said locking lever, said detent being insertable into said hole, said lever comprising two arms, one of which includes said detent and the other of which includes at one end an abutment element which extends parallel to the pivot axis of said lever, trip means on said second carriage to alternately urge said element in either of opposite directions in correspondence to which said detent is either urged into or out of said hole.

9. The machine of claim 8, wherein said trip means comprises a pivoted plate having peripherally spaced notches, said plate being pivotable to either a first or second position each one of which corresponds to one of said notches abutting against said abutment element, a spring means connected to said plate for alternately urging said plate to either of said positions, a limit stop fixedly mounted on said machine at a location thereon whereby it abuts against said plate and pivots same towards said first position when said second carriage is proximate to its end position, said first position being that in which said plate urges said abutment element in a direction whereby said detent is disengaged from said hole.

10. The machine of claim 9, wherein said plate comprises two peripherally spaced stepped edges, a different one of which is adapted to abut said limit stop in said first and second plate positions, with said plate being in said first position one of said stepped edges lockingly engaging said limit stop and thereby preventing movement of said second carriage towards its starting position, a hand lever on said second carriage for forcing said plate to said second position.

11. The machine of claim 4, wherein said resilient means urging said drum to rotate comprises a spirally wound spring connected at one end'to said, drum and at its other end to a fixed part of said second carriage.

12. The machine of claim 7, wherein said locking ring is a split ring which is rigidly secured about an integral hub portion of said drum by means of a screw which passes across the split end of the ring, said screw being loosenable to loosen said ring about said hub, and said drum being rotatable in order to change the distance between said carriages while said ring is held stationary with said interengaging means being in engagement with each other.

13. The machine of claim 5, wherein said second carriage includes a stationary guide for guiding said flexible cable over said drum as said drum rotates.

14. The machine of claim 9, wherein said spring means comprises a coil spring connected at one end thereof to .a stationary point on said carriage and at the other end thereof to a point on said plate, said points defining a straight line which shifts to opposite sides of the rotational axis of said plate when said plate is pivoted from one of said positions to the other, whereby said spring performs a tumbling action to urge said plate either clockwise or counter-clockwise depending upon position of said straight line relative to the rotational axis of said plate.

15. In a fabric sewing machine which includes a sewing needle and an automatic fabric feeder for advancing a fabric under said needle in a feed direction, said feeder comprising: first and second carriages each comprising a fabric holding clamp and each being independently reciprocable toward and away from each other during machine operation, drive means to reciprocably drive said carriages along said feed direction and means to maintain said carriages spaced apart a fixed distance relative to each other, release means to permit said carriages to move relative to each other during machine operation, and

means to automatically re-establish said fixed distance subsequent to said carriages having moved relative to each other.

16. The sewing machine of claim 15, including adjustment means whereby said fixed distance may be varied so that a different, length of fabric can be clamped between said carriages in accordance with a respective different fixed distance therebetween.

17. The sewing machine of claim 1, wherein said connection means transmits driving force from said first carriage to said second carriage, said second carriage being otherwise independent of said drive mechanism.

References Cited UNITED STATES PATENTS 2,899,919 8/1959 Myska 112-2 X 3,053,204 9/ 1962 Kelemencky ll22 3,068,816 12/1962 McBean et al. 112-2 X 3,073,267 1/1963 Reeber et a1 112-2 3,082,719 3/1963 Zeitlin 112-65 3,162,154 12/1964 Medofi 112-2 PATRICK D. LAWSON, Primary Examiner.

HERBERT F. ROSS, Examiner, 

15. IN A FABRIC SEWING MACHINE WHICH INCLUDES A SEWING NEEDLE AND AN AUTOMATIC FABRIC FEEDER FOR ADVANCING A FABRIC UNDER SAID NEEDLE IN A FEED DIRECTION, SAID FEEDER COMPRISING: FIRST AND SECOND CARRIAGES EACH COMPRISING A FABRIC HOLDING CLAMP AND EACH BEING INDEPENDENTLY RECIPROCABLE TOWARD AND AWAY FROM EACH OTHER DURING MACHINE OPERATION, DRIVE MEANS TO RECIPROCABLY DRIVE SAID CARRIAGES ALONG SAID FEED DIRECTION AND MEANS TO MAINTAIN SAID CARRIAGES SPACED APART A FIXED DISTANCE RELATIVE TO EACH OTHER, RELEASE MEANS TO PERMIT SAID CARRIAGES TO MOVE RELATIVE TO EACH OTHER DURING MACHINE OPERATION, AND MEANS TO AUTOMATICALLY RE-ESTABLISH SAID FIXED DISTANCE SUBSEQUENT TO SAID CARRIAGES HAVING MOVED RELATIVE TO EACH OTHER. 